OCC Forums

chain dimensions specification


By owenp - 9 Dec 2016

Dear all,

i m currently renewing the windlass and chain on my boat , Danú.
boat is 17.3 tonnes , 13m , steel.
looking at various information i have read it seems that given the weight and length that 10 mm g40 calibrated chain would be suitable . I am thinking of putting in 80 m chain.

does any one have any advice on whether to go to 12 mm or 10mm ?

Regarding the windlass, I like keeping with the manual anchor idea yet most windlasses available are electric.
There is a company still producing simpson lawrence seatiger 555 windlasses (SLSPARES UK) which seem to have a good reputation.

has anyone seen these in action ?

great to hear your suggestions / opinions on this.


Peter Owens , Galway , Ireland
By Dick - 9 Dec 2016

Hi Peter,
I am currently writing an article on the choosing of chain, and would be happy to send you a copy off line if you send an email to me at Alchemy128(at)gmail.com.
The gist is to choose chain by strength and not by weight. The argument for weight is it produces catenary. This argument falls apart in near gale conditions (when you need catenary most) when the chain regularly gets 2-blocked (stretched link to link) in most reasonable scopes. Your snubber then becomes crucial in absorbing and averaging loads as the catenary is for all practical purposes non-existent.
I have a similarly sized boat (12.2m and 16+ ton) and am quite content with 5/16 inch G40 from a good manufacturer. I have 80m and will get 100m when I replace it. My chain is 16yo and has been re-galvanized once and has served through thousands of nights at anchor and many gales.
I would suggest 10mm G40 (plenty strong) from a good manufacturer and put your weight and money into a good designed anchor. Mine is a 35kg Spade and I have been using Spades for almost a decade now and think it is the top bower available presently.
We spent a week in Galway this last summer and the whole summer on the west coats of Ireland. Marvelous.
My best, Dick Stevenson, s/v Alchemy
By simoncurrin - 9 Dec 2016

I know you are planning to use this in Greenland 's testing fjords. I would definitely go for a 100m if you have the room and using a smaller, high tensile, chain may give you enough locker room to do this. That 's what we did and kept our old chain for backup in case we lost bower for any reason. Also, with long chains, heavy anchors and solid cold winds I can 't think why you wouldn 't want a powered windlass. Presumably to keep your crew fit for those big wall climbs?
By Dick - 9 Dec 2016

Hi Peter,
If heading out of Europe to deep water anchorages and the type of challenges that Greenland is likely to have, then I very much echo Simon 's advice for 100m I would also believe a powered windlass (money aside) to be considered a safety issue. Sometimes, in a midnight fire drill, one needs to get the anchor handled quickly. Pumping a long handle on heaving fore-deck for periods of time is a recipe for an accident.
My best, Dick
By simoncurrin - 10 Dec 2016

Peter I am not sure if you have already seen this thread which discusses G70 chain at some length. https://www.forum.oceancruisingclub.org/anchors-and-anchoring/760-g70-anchor-chain.html
By owenp - 12 Dec 2016

thanks Dick and Simon for your replies.

I think now that 10 mm of G40 is the best option. I can see the logic in the G70 and 8mm though but we have plenty of space in bow for 100 m .
re windlass I can see that not many share my view on manual ones! i suppose i am thinking of simplicity over another electrical setup. cost is a consideration with the lofrans electric windlass for our boat coming in at €2500. Also and perhaps a bit on the masochistic side, having used manual windlasses for ever , they are one of the few ways on a boat to give the arms a work out ! but repeated anchoring in stiff conditions is not fun i admit. Will think a little more on this one.
all the best

By Dick - 15 Dec 2016

Hi Peter,
You bring up another safety issue with having a powered windlass that I neglected to mention before. I know you are clear, but I wish to underline it for others who may be reading. There is certainly an argument for simplicity, less expense and for exercise, but it should be kept in mind that one of the appreciations most mentioned by those who switch from manual to powered winches is the ease with which they are able to re-anchor. First or even second choice anchoring spots do not always feel right when settled and to quickly and easily adjust can be a good thing. That said, adding a powered windlass is no small project.
My best,
Dick Stevenson, s/v Alchemy
By Dick - 15 Dec 2016

And at the risk of belaboring a point, this was started by considerations of anchoring deep. For those considering this dilemma with windlasses, one should go somewhere and either anchor deep or go to deep water and drop your bower and 25-30 meters of chain over the bow and then use the manual windlass to retrieve. Even my quite powerful electric windlass starts to strain at this level of weight and retrieval time increases a great deal.
Enough already, Dick
By owenp - 15 Dec 2016

Hi dick

thanks for your responses. i think i am getting around to the electric idea. The last person i talked to about all this told me to throw away the cqr, or use it as a garden ornament along with the fishermans and get a spade or vulcan ! i know this brings up a new topic on choice of anchor. Whats your thoughts on this?
all the best

By simoncurrin - 15 Dec 2016

Where you are heading (Greenland) there 's loads of rock and kelp so all anchors will have limitations. We use a 45kg Manson which is similar to the ubiquitous Rocna. Might be worth keeping you Fisherman 's to cope with the kelp?
By owenp - 15 Dec 2016

Hi simon, dont worry not getting rid of it just yet .

Just its a minefield of opinions out there ! t
he spade does get good recommendations though and apparently doesnt do to badly in weed .
main thing about the fishermans is the hassle in getting it on deck and deploying . i have done a fair few miles to date and have yet had necessity to use one. It could be greenland though....
any thoughts on the vulcan which i think is the rocna upgrade?
By simoncurrin - 15 Dec 2016

Peter the post below is from Dick who is struggling to access the Forum. By the way my mention of a fishermans was tongue in cheek. I made a dinghy mooring out of mine some years ago. Great for that!

Hi Peter,

Yes, the CQR should be relegated to a hood ornament. I have been using Spades for 7-8 years now and they is a huge leap in safety over CQRs and Bruces (I used to own both and used the CQR for decades) and Deltas and others from that generation.

I believe that after design, weight is most telling in getting through weeds and kelp. A fisherman may get through the kelp or hook on a rock, but I want an anchor that will, when it gets through, dig in and hold the way a Spade does. Further, the Spade with its weight concentrated in the tip (and my larger than normal size), has been extremely effective at penetrating weed and kelp.

A couple of seasons ago I got rid of my fishermans (an 80 pound Luke) for the reasons you stated as well as I had a better solution. I put my 66 pound Spade in spares where the Luke used to be (I think it is a better all-around anchor and always would choose it over a Fishermans and, like the Luke, it comes apart so handling is far easier) and upgraded to a 35 kg/77 pound Spade. This is on a 40 foot/16 ton boat. This has worked out great. Much more holding power (I think it goes up geometrically) for only 11 pounds more weight. (And actually my “spare” is now 14 pounds lighter and I think more versatile and effective.)

All the new generation anchors are far superior. Rocnas are great but have a reputation of (quite rarely but occasionally) failing to re-set after a wind shift (see the Rocna stream on the OCC forum). I do not have experience with Manson or Vulcan. The best discussion of anchors and anchoring (along with a wealth of other sailing data, especially high latitude sailing) by very experienced sailors is on the Attainable Adventure Cruising web site. It will cost ~$20, but I suspect you will feel it was worth every penny.

My best,

Dick Stevenson, s/v Alchemy
By Alex_Blackwell - 16 Dec 2016

By Alex_Blackwell - 16 Dec 2016

i just spent the past hour writing a lengthy reply only to have an error message - probably same as Dick.

sorry cannot rewrite - no time
By Ginger - 16 Dec 2016

Hi Alex,
How very infuriating. I am sorry to miss your thoughts as they always contribute.
In response to this problem, I have started writing off line all my comments and then C&P 'ing them into the forum for posting and in that way ensuring I do not lose a lot of work.
My best, Dick
By Alex_Blackwell - 17 Dec 2016

even cutting and pasting does not work

perhaps my reply is too long?
By Alex_Blackwell - 17 Dec 2016

Hi Peter – am taking another stab at a reply, using Dick’s suggestion of drafting offline. That failed, so I will post it in sections – apologies for this.

First of all I do concur with all of Dick 's & Simon 's comments & suggestions.

As to the Vulcan (we have one), as I mentioned when we spoke, it is indeed an excellent anchor. Like all scoop type anchors it sets and holds very well. It was designed by Peter Smith for boats that cannot handle a roll bar – powerboats for the most part. It did fit ok on our bow roller, but our boat is old and quite pointy. It would not work on boats with plumb bows, unless they have bow rollers.

As to your comment re cost, please consider what you think your life is worth, plus what your boat and its contents are worth. Then consider what might be willing to spend on insuring these. If your anchor fails in a storm, there is a pretty good chance you will die – particularly when sailing hi high latitudes.
By Alex_Blackwell - 17 Dec 2016

With regards to your anchoring tackle, following are my thoughts:

Starting at the bottom:
1.   Lose the CQR (period). Even if it has not done so already, it will drag, break out and not reset, or just not set in the first place.
2.   Lose the Fisherman / Luke. You will never use it. It is unnecessary weight. It looks great on the lawn.
3.   With a view to my comment re cost:
a.   Buy a modern scoop type anchor as your primary. Yes, go up one size on the manufacturer’s recommendation. There are many options: Spade, Ultra, Rocna, Vulcan, Supreme, Mantus, and many more.
i.   Do not get a plough (ploughs are meant to plough (=plow))
ii.   Do not get a claw (set fast but hold poorly)
b.   Buy a dismantelable scoop type anchor as a secondary. Spade and Mantus are options (we have both). However, ensure that the bolts are drilled and pinned. Do not rely on nyloc nuts.
c.   Buy a lightweight (Aluminium) Fortress anchor (we have) as your tertiary. This holds as well as a scoop in softer bottoms. It is also the only anchor sized to your boat that you can easily deploy from your dinghy – as a stern anchor or second bower.
4.   When anchoring in potentially foul ground (like rocks, or near mooring fields) always deploy a trip line. If your anchor snags something, you will be glad you did.
a.   You can also consider adding an Anchor-Rescue or Anchor-Witch to your tackle. (we have both and have been using the Anchor-Rescue all this past season) These devices enable you to lower a messenger line down your rode and then lift the anchor by its crown without disconnecting the rode from the shank.
By Alex_Blackwell - 17 Dec 2016

The middle bit (the rode) has been covered quite adequately, and I do agree with the above comments. Here are some further suggestions:
1.   Have one further full length rode ready to deploy. This can be rope with a length of chain.
a.   Rope should ne nylon – not an old halyard or sheet. These do not stretch and do not have any energy absorption. Also do not use polypropylene, although cheap and stretchy, it degrades with UV light.
2.   Have a further full length rode as a backup. If you have a Fortress, this need not have a length of chain, though having the chain is a good idea.
3.   Consider having one more rode stored aft for stern anchoring or tying off shore, aka med mooring.
At the top end, make sure you have a long snubber. In a blow, your chain rode will go bar taut. Discussions on catenary alleviating this are nonsense in a strong blow. You must add elasticity to your rode to prevent gear failure. You can attach the snubber to the rode with either a chain hook, or with a rolling hitch.

Apologies Dick, but your one recommendation to subscribe to AAC I cannot concur with. You can get more and better information right here on the forum. There are also websites that have equally good information at no charge.
By Dick - 18 Dec 2016

likewise splitting up a comment
Hi Alex,
Thanks for your contributions to the discussion and I agree with your recommendations about a lightweight kedge: ours is a Fortress.
It is with some curiosity that I note that this is the second time that you have gone after the Attainable Adventure Cruising web site on the pages of the OCC Forum: both times to me unwarranted and un-necessary. The site is a valuable asset to the cruising community, especially for offshore cruisers and those who go to challenging parts of the oceans. It is run by an OCC member who speaks highly of the OCC on his site.
By Dick - 18 Dec 2016

The first instance was when you suggested that the AAC site’s principle author had questionable conflicts of interest in his reporting that Rocna anchors occasionally had difficulties re-setting after a significant wind shift. I pointed out that he was merely reporting the accumulating evidence from other sources and listed the sources for others to see and evaluate. Further, an OCC member subsequently reported just this resetting problem occurring. I requested you visit the site and review the data. I do not know whether you did so, but I have noticed no retraction nor apology on the, to my mind, completely unwarranted suggestion that his reporting was influenced by a conflict of interest.
By Dick - 18 Dec 2016

Now there is, at the end of your comment in this stream, again to my mind, a gratuitous suggestion not to join the site and a comparison to the OCC Forum as having “more and better” information. Why do that? If you feel the site passes on poor information, please point out what you perceive as errors. I very much do not think it necessary to pit the sites against each other nor do I think a $20 dollar yearly fee, in the scheme of boat expenses, worth even any comment or consideration. I participate and contribute a great deal to the OCC forum and I do the same at AAC’s site. I would want to put your “more and better” comment aside, an evaluation I very much disagree with, but that is really beside the point. For you to go out of your way to undermine my suggestion that someone may find the AAC site a helpful spot for additional information, I find undermining of my trying to be of service on the OCC site.
My best, Dick Stevenson, s/v Alchemy
By Alex_Blackwell - 18 Dec 2016

Peter and Dick
I am sorry this discussion has now gone sideways.
For the record, I have nothing against AAC. We were early supporters of their Norwegian Cruising Guides, and have published very positive articles about them.
All I am objecting to is pushing commercial websites on this forum. We do not push our non-commercial sites, which have copious free information, as we do promote our books on them. We have long used similar guidelines as on the OCC FB page when posting on this forum.
Nuff said - discussion closed
Happy Christmas
By owenp - 19 Dec 2016

thanks very much for all the comments, this has been very helpful.

all the best,

By Dick - 19 Dec 2016

Hi Alex,
I respectfully suggest the issue not be closed. It is certainly not from my point of view.
There are a couple of issues:
The most important one is the undermining my comments and suggestions on the OCC site. I participate solely on the OCC Forum to convey the best information and thoughts I have when members ask questions, and I try to differentiate the two. If you think the directions I point have problematic elements for the handling of our vessels, then, by all means, challenge my thinking. If you think other venues have better information, please direct the reader to the site and the specific area where the relevant information resides.
But please do not undermine my suggestions. If I wish to suggest that someone might benefit from a source of information where I have absolutely no commercial interests, I would want to not have that interfered with any more than I would want censored a suggestion that someone might consider buying a product such as a Spade anchor (or a Rocna or a swivel etc.). I would also want to be free, and have others be free, to mention the benefits of reading yours and Daria’s book or reading another book by an OCC member (or any other book, magazine, web site) if I considered them likely to benefit cruising knowledge.
As an aside, I would think that AAC would be just the kind of endeavor that OCC would support. The site is solely to promote offshore sailing especially in challenging areas (high latitude) where the principles have much experience. AAC’s principles are OCC members. Membership fees are quite modest and were instituted to cover expenses for the running of the site. I would suspect that an evaluation of their per/hour earnings, if any, would be laughable or in the negative realm. That the AAC is rapidly becoming (there already in my evaluation) the premier go-to site for honest expert evaluations of products/techniques/safety pertaining to offshore sailing: all that and more makes the site a no brainer in my mind for many OCC members.
But evaluation of sites aside: again, my interest is just to have the freedom to convey to any reader the best information and thoughts I have that promotes cruising. I find any restrictions in doing so not in the best interests of the OCC nor of its members. I welcome challenges to my thinking and conclusions, but I resist restrictions and censorship such as you feel inclined to impose. I believe this is important and is not closed.
Respectfully submitted, Dick Stevenson, s/v Alchemy
By simoncurrin - 19 Dec 2016

Alex & Dick,

From my perspective as Forum moderator I am always delighted to accept both of your contributions to this Forum as these contributions are always thoughtful, thought provoking and based on decades of experience.

I would just like to correct a possible misunderstanding. Unlike the OCC Facebook page the OCC Forum has never banned commercial use or self promotion. Indeed it contains many links to items for sale etc. From time to time we have even allowed guest posts by businesses where the post is clearly in the member 's interests. Unlike FB we do not risk being plagued by a deluge of dubious worth and if we were it would be easily dealt with by Moderation. I know these things were much discussed during the summer on Facebook and I think that is where some of the confusion arises but I am happy to say that the Forum is, and hopefully will remain, far less regulated.

Please both continue to share your experiences and make this Forum a vibrant and useful resource for our members. I know that our members are discerning enough to distinguish between genuine advice based on real life experience and shallow commercial interest. To date I have seen none of the latter.

If we need to discuss a perceived need to increase the rules within this Forum then we can open a separate thread to discuss this elsewhere. I suggest the "Development" thread. However I firmly believe that additional regulation is not required as this Forum is not as vulnerable as our FB page.

Thank you both for your excellent posts.

By Dick - 19 Dec 2016

Hi Peter,
You are very welcome. I am sorry that this discussion went, as Alex says, a bit sideways, although some important (to me) clarifications emerged. I hope it did not unduly derail any questions or thoughts you may have had. Please let us know what choices you make down the line.
My best, Dick Stevenson, s/v Alchemy
By Dick - 20 Dec 2016

Hi Simon,
Thanks for the clarification. The guidelines you spell out are right in line with what I consider reasonable and right in line the type of atmosphere in which I want to participate.
Thanks, Dick
By simoncurrin - 2 Jan 2017

I am trying to post this on the OCC forum chain discussion but it doesn 't work. Would you please post it for me? Thanks

Best wishes,
s/v Dawnpiper

I want to add several comments and suggestions. I also had problems getting my Rocna 88 lb anchor to set unless backing extremely slowly. S/v Dawnpiper is a Trintella 47, 40,000 lbs.
The Rocna also failed to reset when the tide turned, and I dragged. I was so disappointed in the Rocna that I switched to a galvanized Spade 99 lbs. I do not use a swivel as I have seen failures in stainless swivels The chain is stabiled by a roller with a notch in it for the chain so it never seems to come up twisted, or need a swivel. My spare is the Spade aluminum 66 lb, and kedge is the Fortress Fox-37.
I concur with Dick that the Morgan 's Cloud AAC site is excellent: everyone could benefit from the careful discussion there.
The end of my chain is attached by a heavy line to a bulkhead below with the length adjusted to keep and ensure the chain stays on the gypsy. A 50 foot length of yellow polypropylene 1/4 inch line is affixed to the end of the chain. I can cut the heavy securing line at deck level if I ever have to loose my bower in an emergency, and the polypropylene floating line allows later easy retrieval.
Best wishes
Charles Starke, s/v Dawnpiper
By Ian.Park - 2 Jan 2017

Just a thank you to Charles for the tip on ensuring the bulkhead attachment just appears above deck. I can see the enormous value in not having to race below with knife in hand to lose the anchor! Just a slight concern with the 50ft floating line and the danger to any boat 's propeller? Wouldn 't a handy fender be a better retrieval marker?
I have a Spade and a Rocna. Both so far have been equally impressive. However the hollow shank on the Spade has bent slightly, probably when caught on a rock at the change of tide.
In relation to swivels (I do use one) it is important to check frequently that the securing screw does not work loose, but equally importantly that there are a few links of chain between the anchor shank and the swivel. If the swivel is connected directly to the shank it can impose a sideways pull across the swivel joint rather than maintaining an in line pull.
By Alex_Blackwell - 2 Jan 2017

Hi Ian & Charles
As an anchor marker/trip line I would recommend a sinking (nylon) rope with a buoy. a floating line is always asking for trouble. Just go anywhere that there are lobster or crab fishermen to see what it is like. As I believe I mentioned earlier, we also add 1/2 pound lead weight about 2m down the line just to be sure that the top end of the line is vertical.

Ian: please bear in mind that any bent or damaged anchor cannot and will not perform as intended by the manufacturer.
Also: the most common way that anchors are bent is by the skipper powering over the anchor in the ill-conceived notion that this is the best way to break it out of the bottom.
By starke - 2 Jan 2017

Hi Ian

Thanks so much for the good words. The idea of the yellow polypropylene line is to make it easy and quick to loose the bower. There usually isn 't time to tie on a fender, and I would not want someone else to retrieve my anchor or investigate my fender. The light line makes it inconspicuous and unlikely for another boat to foul in the conditions forcing me to loose the bower.
I don 't trust all the connections necessary for a swivel. One shackle is enough for me. My chain runs through a chain lock, and then under a roller with a square notch that fits the chain, then over a roller at the bow. So it 's always retrieved without a twist by time the anchor is under the bow.

Best wishes,
Charles Starke
s/v Dawnpiper
By Dick - 2 Jan 2017

Hi Ian,
Please see my comments to Charles in prior email with regard to securing ropes and where to find pros & cons of the variations on trip line.
I agree with Alex as to the functionally of even minimally altered anchors: it may be fine, but not an area to fool with.
I would hope that Spade would replace the shaft at a reasonable price. They are one of the few anchors where it is reasonable to buy parts, so I hope they are easy to work with in this area. I was impressed with their response to the rust on my very well used 8 years old Spade last year when they just replaced it. (Early Spades were not well galvanized, a largely cosmetic issue, and they allowed me to keep the old anchor which is now a spare.)
Let us know how this unfolds, if you will.
My best, Dick Stevenson, s/v Alchemy
By simoncurrin - 2 Jan 2017

Posted on Behalf of Dick
Hi Charles,

Thanks for the field report. I am surprised that you had trouble setting your appropriately sized Rocna as that is a function that it usually does superbly. As to the re-setting, this seems to be a problem with Rocnas which rarely, but occasionally, occurs and you are not alone in switching to a Spade.

I applaud your moving up a size as weight in the anchor pays huge dividends in keeping the boat in one place: far more benefit than any downside of adding 11 pounds to the bow.

As to swivels, not only are they contraindicated if they are stainless steel (which, to my evaluation), has no business in a ground tackle system, but they increase complexity and serve no function (see swivel area in Forum for details).

It is wise to have the end-of-chain securing rope emerge onto the deck for being able to quickly cut: make sure that the knot attaching rope (especially as you specify heavy line) to chain is executed in a fashion to not hang up on its way to the deck. I have a visible indication on the chain about 3 meters from the end to make sure I am prepared for the rope to emerge as the chain can be coming out fast in a dump.

As to a polyprop floating line, trip lines and their cousins are a complex subject, again addressed elsewhere in the forum.

My best, Dick Stevenson, s/v Alchemy